Comparison of Feynman Variance-To-Mean Measurements Using Measured and Simulated Data
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Measured and simulated list-mode data from the NPOD detector system were compared for subcritical systems. Five BeRP ball configurations reflected by polyethylene are investigated in this work. The simulated data were calculated using the MCNP multiplication patch developed at LANL. In addition to comparing the moments of the counting distributions, a full analysis was conducted to infer the multiplication of each system using both the Hansen-Dowdy and Hage-Cifarelli formulisms. Several of the parameters that are input into these methods were also varied to determine their affect on the system multiplication. The main parameters investigated included the system source strength, reflector transmission, and the average number of neutrons released per 239Pu fission ($$\nu$$). It is shown that when comparing the measured and simulated data while using the same method and parameters the inferred multiplication values agree within 5%. The measured and simulated multiplication values differ more as the reflector thickness increases. The moments for the simulated data were higher than the measured data for all of the configurations and also disagreed more as the reflector thickness increased. The analysis method and parameters used can lead to a large spread of inferred multiplication values. In the future more configurations will be analyzed in a similar manner and a detailed uncertainty analysis will be performed.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
- DOE Contract Number:
- AC52-06NA25396
- OSTI ID:
- 1083883
- Report Number(s):
- LA-UR-11-04251; LA-UR-11-4251
- Resource Relation:
- Conference: ICNC '99: International Conference on Nuclear Criticality, Edinburgh, Scotland (United Kingdom), 19-22 Sep 2011
- Country of Publication:
- United States
- Language:
- English
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